Did you know?Cabinet Absence
In lieu of Daniel Pesina (Johnny Cage's actor) fallout, the Mortal Kombat cabinet Liu Kang drops in game is missing one character who appears on it in real life.

Lost Kombatants
Ed Boon and the Mortal Kombat crew were working on several characters in Mortal Kombat vs. DC Universe that would have served as downloadable content, including Quan Chi, Harley Quinn, Kung Lao, Mr. Mxyzptlk, Lobo, and Doomsday. However, with Midway's failing financial situation, and the advent of work beginning on the next entry in the series, the characters were scrapped. Reportedly, Quan Chi and Harley Quinn were the closest to completion.

No More Violence!
In order to facilitate the "T" rating DC Comics required for the use of their license, several Mortal Kombat characters' signature fatalities were altered in Mortal Kombat vs DC Universe. In Jax's Head Smash Fatality, he flattens his opponent's head like a pancake rather than exploding it to pieces, none of the opponent's flesh burns off in Scorpion's Toasty! and Sonya's Kiss of Death Fatalities, and the outcome of Raiden's Electrocution and Kitana's Kiss of Death Fatalities was changed from the opponent exploding to pieces to them becoming a skeleton.

The Killing Joke
While the Joker himself could not return in the series M-Rated follow up to MK vs DC, his infamously censored Fatality (Bang, Bang) did. Referred to as "a trick he picked up from previous opponents", Shang Tsung can morph into a very Joker-like clown and recreate the comedic execution verbatim, complete with win pose.